Atype of drug that can alter thoughts moods and perception is known as

The answer is hallucinogen. A hallucinogen is a psychoactive agent which can cause hallucinations, perceptual anomalies, and other substantial subjective changes in thoughts, emotion, and consciousness.

This gel or liquid can be placed under the tongue of an unconscious person. this is important because you should never pour anything down the throat of an unconscious person-- s/he could choke.